Last weekend, Las Vegas hosted hundreds of teams from across the country during the last evaluation period of July. Rivals.com was in attendance, catching as much of the action as possible, and here's a look at what we learned, specifically how we are feeling about the top spots in the classes of 2014, 2015 and 2016. Only rising senior Jahlil Okafor appears to be a lock.

Okafor deserves to remain in top spot

One of the players we absolutely had to see in Las Vegas was the one we have ranked No. 1 in the 2014 Rivals150, Okafor. For much of the spring Okafor was battling injuries, and USA Basketball duties took him away during much of June, meaning he was absent from some of the bigger evaluation camps.

The 6-foot-11 center was playing with his club team, the Mac Irvin Fire, in Vegas. After taking another couple of long looks at him, Rivals.com feels Okafor has done more than enough to retain his top billing in the class.

First, there just haven't been many players like him in quite some time. Okafor is a true back-to-the-basket, low-post presence, and he is a reliable scorer when given the ball. Okafor isn't just big and strong. He has a skill level that is absolutely off the charts.

Okafor scores comfortably with either hand around the basket, he can make short jumpers, and he's become adept at using a dribble or two to shake defenders. He plays through contact, he passes well, and he always rebounds well. Okafor has continued to reshape his body, and we were impressed with the way he moved his feet up top when he had to help on defense in ball-screen situations.

Bottom line, Okafor entered the summer as the best player in the country and it is our opinion that he has done enough to retain that status.

Newman and Zimmerman in close battle for 2015's top spot

As things stand, Malik Newman is the king of the class of 2015. The 6-foot-3 combo guard did exactly what was expected of him during the summer.

He scored the ball at will, and he proved to be one of the most unguardable players on any level of high school basketball. Whether it was with USA Basketball's 16U team, the Jackson Tigers, Mo Williams Elite or at camps such as the LeBron James Skills Academy, Newman went out and got buckets. Whether it was off the dribble, in transition or with deep jumpers, Newman scored in every way possible and looked very good doing so.

While Newman's scoring ability is unquestioned, there are a few things to be determined. The biggest questions would be whether he can effectively play the point full time and if he's big enough as a shooting guard on the highest level? There's no doubt that Newman can handle the ball, but he's a scorer at heart so he would need a shift in his game to be a point guard. As a shooting guard, he's on the small side for the highest level. But he's entering his junior year and still has time to grow.

Right now, Newman's biggest competition for the top spot remains the nation's No. 2 player in 2015, Stephen Zimmerman.

The 6-foot-11 center from Las Vegas (Nev.) Bishop Gorman can't dominate as a scorer like Newman can, but the rest of his game is rounding out quickly. He has started to knock down jumpers with confidence and to assert himself as a shot blocker. Zimmerman is an outstanding passer, and he is playing with more physicality each time as he perfects a nicely blended inside/out game. Zimmerman needs to get stronger, and at times his impact as a scorer isn't quite what it could be.

So, which guy deserves to be No. 1 at this point? Based on current body of work, Newman probably gets the edge. For ultimate upside and long-term potential, Zimmerman could be the answer, but Newman has plenty going for him in those areas as well. We're leaning toward Newman hanging on to the top spot for now, but Zimmerman is making an awfully compelling case and the decision won't be finalized for the next month or so.

Jackson throws his name into the hat for 2016

Entering the summer, the thinking had been that power forward Harry Giles was the frontrunner to debut at No. 1 in the class of 2016. Before suffering a knee injury playing with USA Basketball, Giles seemed to be well on his way to solidifying that thought. Also working his way into the mix as the end of summer neared was 7-footer Thon Maker.

An electric athlete, Jackson made staggering improvement from October to May to the end of July. Jackson always has put his quickness, length and bounce to good use, and he is a high-end finisher. However, we didn't expect to see the polished ball handler, outstanding wing defender and scorer with upside that we saw when he ran with Dorian's Pride in Las Vegas. His package of size, athleticism and skill makes him the prototypical shooting guard prospect, and he could be the best overall prospect at that position regardless of class to go with maybe being the No. 1 overall player in 2016.